What are the benefits of a electrocardiogram?

Question

What is an electrocardiogram and how does it work?

Describe two ways electrocardiograms benefit us?

Answer 1

it can show current & past heart damage, but is only a tool in a diagnosis of a patient.  visit the local ambulance service or ER for a quick lesson.

Answer 2

Electrocardiograms (ECG, EKG) provide snapshots of the electrical rhythm of the heart.  The hearts muscle cells have electrical potential, just like the cells in the body.  A normal heart electrical system produces a characteristic p-qrs-t wave pattern as the atria and ventricles depolarize and repolarize.  

An ECG is perfomed by placing 4 electrodes, or leads on a patient's limbs, away from bony prominences.  The leads produce the characteristic pattern based on the principle that the electrical pulse moves from the atria and down towards the ventricles.

ECGs are able to detect any cardiac dysrhythmia, again based on the principle that each dysrythmia produces different electrical patterns.

ECGs are also potentially able to diagnose an MI (myocardia infarction), but not always.  STEMI (ST-elevation MI) shows on an ECG, but a patient can suffer an MI and have in not be visible on the ECG.  This is also called a non-STEMI.